Vertical Laminate Noodle for High Capacity Pull-Off for a Composite Stringer

ABSTRACT

An apparatus comprises a composite elongate member, a channel, and a number of composite structures. The composite elongate member has a side configured for attachment to a surface of a structure. The channel is on the side and extends along a length of the composite elongate member. The number of composite structures is configured for placement in the channel and configured to attach a portion of the side of the composite elongate member to the structure. The number of composite structures has layers oriented substantially perpendicular to the surface of the structure. The number of composite structures is configured to increase a capacity of the composite elongate member to withstand forces that pull the composite elongate member away from the structure.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation-in-part of patent application Ser.No. 13/111,375, filed May 19, 2011, entitled “Aircraft Structure forHigh Capacity Pull Off”, which is incorporated herein by reference.

BACKGROUND INFORMATION

1. Field

The present disclosure relates generally to aircraft and, in particular,to aircraft structures. Still more particularly, the present disclosurerelates to stringers and other structural designs for an aircraft.

2. Background

Aircraft are being designed and manufactured with greater and greaterpercentages of composite materials. Some aircraft may have more than 50percent of their primary structures made from composite materials.Composite materials may be used in aircraft to decrease the weight ofthe aircraft. This decreased weight may improve payload capacities andfuel efficiencies. Further, composite materials may provide longerservice life for various components in an aircraft.

Composite materials may be tough, light-weight materials created bycombining two or more dissimilar components. For example, a compositematerial may include fibers and resins. The fibers and resins may becombined to form a cured composite material.

Further, by using composite materials, portions of an aircraft may becreated in larger pieces or sections. For example, a fuselage in anaircraft may be created in cylindrical sections that may be put togetherto form the fuselage of the aircraft. Other examples may include,without limitation, wing sections joined to form a wing or stabilizersections joined to form a stabilizer.

A stringer is an example of a component that may be manufactured fromcomposite materials. A stringer is an elongate member and is configuredfor attachment to another structure, such as a panel. For example, astringer may be attached to a skin panel for an aircraft. This skinpanel may be used in a wing, fuselage, or other component in theaircraft. The stringer also may help carry and/or transfer loads. Forexample, a stringer may transfer a load from a skin panel to anotherstructure. This other structure may be, for example, a frame or rib.

Designing stringers with a desired weight and performancecharacteristics may be challenging. For example, a stringer with desiredperformance characteristics may be more complex or weigh more thandesired. With increased complexity, time and cost for manufacturing astringer also may increase.

If the stringer has a desired weight, performance characteristics may besuch that additional stringers may be required where a single stringeris desired.

Therefore, it would be advantageous to have a method and apparatus thattakes into account at least some of the issues discussed above, as wellas possibly other issues.

SUMMARY

In one advantageous embodiment, an apparatus comprises a compositeelongate member, a channel, and a number of composite structures. Thecomposite elongate member has a side configured for attachment to asurface of a structure. The channel is on the side and extends along alength of the composite elongate member. The number of compositestructures is configured for placement in the channel and configured toattach a portion of the side of the composite elongate member to thestructure. The number of composite structures has layers orientedsubstantially perpendicular to the surface of the structure. The numberof composite structures is configured to increase a capacity of thecomposite elongate member to withstand forces that pull the compositeelongate member away from the structure.

In another advantageous embodiment, a structural system for an aircraftcomprises a composite elongate member and a filler structure. Thecomposite elongate member has a base section and a vertical section inwhich the vertical section extends away from the base section in adirection substantially perpendicular to the base section to form aT-shape. The vertical section meets the base section at a first locationof the vertical section and a second location of the vertical section inwhich the first location has a first curved shape and the secondlocation has a second curved shape. The first curved shape and thesecond curved shape have a substantially same radius. A channel isformed between the first location and the second location and extendsalong a length of the composite elongate member. The composite elongatemember has a first Young's modulus. The filler structure comprises anumber of composite structures configured to conform to a shape of thechannel. The number of composite structures has a second Young's modulusthat is within a desired range from the first Young's modulus. Thenumber of composite structures has layers oriented substantiallyperpendicular to a surface of the base section. The number of compositestructures is configured to increase a capacity of the compositeelongate member to withstand forces that pull the composite elongatemember away from the base section.

In yet another advantageous embodiment, a method for increasing apull-off capacity for a composite elongate member is provided. Anaircraft is operated. Responsive to operation of the aircraft, forcesconfigured to pull the composite elongate member away from a structureattached to a side of the composite elongate member are generated. Achannel extends along a length of the composite elongate member on theside of the composite elongate member attached to the structure. Acapacity of the composite elongate member to withstand the forces thatpull the composite elongate member away from the structure is increasedusing a number of composite structures in the channel having layersoriented substantially perpendicular to a surface of the structure. Thenumber of composite structures is configured to attach a portion of theside of the composite elongate member to the structure.

The features, functions, and advantages can be achieved independently invarious embodiments of the present disclosure or may be combined in yetother embodiments in which further details can be seen with reference tothe following description and drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

The novel features believed characteristic of the advantageousembodiments are set forth in the appended claims. The advantageousembodiments, however, as well as a preferred mode of use, furtherobjectives, and advantages thereof, will best be understood by referenceto the following detailed description of an advantageous embodiment ofthe present disclosure when read in conjunction with the accompanyingdrawings, wherein:

FIG. 1 is an illustration of an aircraft manufacturing and servicemethod in accordance with an advantageous embodiment;

FIG. 2 is an illustration of an aircraft in which an advantageousembodiment may be implemented;

FIG. 3 is an illustration of a structural system in accordance with anadvantageous embodiment;

FIG. 4 is an illustration of a perspective view of a structural systemin accordance with an advantageous embodiment;

FIG. 5 is an illustration of a cross-sectional view of a structuralsystem in accordance with an advantageous embodiment;

FIG. 6 is an illustration of a noodle in accordance with an advantageousembodiment;

FIG. 7 is an illustration of a table providing values forcharacteristics for composite layers in accordance with an advantageousembodiment;

FIG. 8 is an illustration of a table of embodiments for values forcharacteristics for composite layers in accordance with an advantageousembodiment;

FIG. 9 is an illustration of a structural system in a wing in accordancewith an advantageous embodiment;

FIG. 10 is an illustration of a structural system in a wing inaccordance with an advantageous embodiment;

FIGS. 11-14 are illustrations of a structural system during thedifferent stages for forming the structural system in accordance with anadvantageous embodiment;

FIGS. 15-17 are illustrations of panels from which composite structuresfor noodles are formed in accordance with an advantageous embodiment;

FIG. 18 is an illustration of a filler structure in the form of a blockdiagram in accordance with an advantageous embodiment;

FIG. 19 is an illustration of a perspective view of a structural systemin accordance with an advantageous embodiment;

FIG. 20 is an illustration of panels from which composite structures fornoodles are formed in accordance with an advantageous embodiment;

FIG. 21 is an illustration of a laminate for a noodle in accordance withan advantageous embodiment;

FIG. 22 is an illustration of a filler structure in the form of a blockdiagram in accordance with an advantageous embodiment;

FIG. 23 is an illustration of a front view of a structural system inaccordance with an advantageous embodiment;

FIG. 24 is an illustration of a table for widths and orientation anglesfor composite layers in a noodle in accordance with an advantageousembodiment;

FIG. 25 is an illustration of a flowchart of a process for increasing apull-off capacity for a composite elongate member in accordance with anadvantageous embodiment;

FIG. 26 is an illustration of a flowchart of a process for forming astructural system in accordance with an advantageous embodiment; and

FIG. 27 is an illustration of a flowchart of a process for forming afiller structure in accordance with an advantageous embodiment.

DETAILED DESCRIPTION

Referring more particularly to the drawings, embodiments of thedisclosure may be described in the context of aircraft manufacturing andservice method 100 as shown in FIG. 1 and aircraft 200 as shown in FIG.2. Turning first to FIG. 1, an illustration of an aircraft manufacturingand service method is depicted in accordance with an advantageousembodiment. During pre-production, aircraft manufacturing and servicemethod 100 may include specification and design 102 of aircraft 200 inFIG. 2 and material procurement 104.

During production, component and subassembly manufacturing 106 andsystem integration 108 of aircraft 200 in FIG. 2 takes place.Thereafter, aircraft 200 in FIG. 2 may go through certification anddelivery 110 in order to be placed in-service 112. While in-service 112by a customer, aircraft 200 in FIG. 2 is scheduled for routinemaintenance and service 114, which may include modification,reconfiguration, refurbishment, and other maintenance or service.

Each of the processes of aircraft manufacturing and service method 100may be performed or carried out by a system integrator, a third party,and/or an operator. In these examples, the operator may be a customer.For the purposes of this description, a system integrator may include,without limitation, any number of aircraft manufacturers andmajor-system subcontractors; a third party may include, withoutlimitation, any number of vendors, subcontractors, and suppliers; and anoperator may be an airline, a leasing company, a military entity, aservice organization, and so on.

With reference now to FIG. 2, an illustration of an aircraft is depictedin which an advantageous embodiment may be implemented. In this example,aircraft 200 is produced by aircraft manufacturing and service method100 in FIG. 1 and may include airframe 202 with plurality of systems 204and interior 206. Examples of systems 204 include one or more ofpropulsion system 208, electrical system 210, hydraulic system 212, andenvironmental system 214. Any number of other systems may be included.Although an aerospace example is shown, different advantageousembodiments may be applied to other industries, such as the automotiveindustry.

Apparatuses and methods embodied herein may be employed during at leastone of the stages of aircraft manufacturing and service method 100 inFIG. 1. As used herein, the phrase “at least one of”, when used with alist of items, means that different combinations of one or more of thelisted items may be used and only one of each item in the list may beneeded. For example, “at least one of item A, item B, and item C” mayinclude, for example, without limitation, item A, or item A and item B.This example also may include item A, item B, and item C, or item B anditem C.

In one illustrative example, components or subassemblies produced incomponent and subassembly manufacturing 106 in FIG. 1 may be fabricatedor manufactured in a manner similar to components or subassembliesproduced while aircraft 200 is in-service 112 in FIG. 1. As yet anotherexample, a number of apparatus embodiments, method embodiments, or acombination thereof may be utilized during production stages, such ascomponent and subassembly manufacturing 106 and system integration 108in FIG. 1. A number, when referring to items, means one or more items.For example, a number of apparatus embodiments is one or more apparatusembodiments. A number of apparatus embodiments, method embodiments, or acombination thereof may be utilized while aircraft 200 is in-service 112and/or during maintenance and service 114 in FIG. 1. The use of a numberof the different advantageous embodiments may substantially expedite theassembly of and/or reduce the cost of aircraft 200.

The different advantageous embodiments recognize and take into account anumber of different considerations. For example, the differentadvantageous embodiments recognize and take into account that thecurrent design of stringers employ the use of composite materialsreferred to as noodles. A noodle is a composite material that may beplaced in an area or channel extending along a length of the stringer orother type of elongate member.

The different advantageous embodiments recognize and take into accountthat currently, these noodles are designed to ease in manufacturingstringers. The different advantageous embodiments recognize and takeinto account that different characteristics or parameters about thenoodle may not match characteristics or parameters in the rest of thestringer with this type of goal in mind.

The different advantageous embodiments recognize and take into accountthat this type of design of the noodle in the stringer may reducedesired performance characteristics, such as the amount of force neededto pull the stringer away from a skin panel.

Therefore, the different advantageous embodiments provide a method andapparatus for a stringer that has a greater ability to withstand forcesthat may pull the stringer away from another structure to which thestringer is attached. The different advantageous embodiments recognizeand take into account that an advantageous embodiment may be applied toany type of elongate member having a base in which a noodle is present.

In one advantageous embodiment, an apparatus comprises a compositeelongate member, a channel, and a number of composite structures. Thecomposite elongate member has a side configured for attachment to astructure. The channel is on the side of the composite elongate memberand extends along a length of the composite elongate member. The numberof composite structures is configured for placement in the channel andto attach a portion of the side of the composite elongate member to thestructure. The number of composite structures is configured to increasea capacity of the composite elongate member to withstand forces thatpull the composite elongate member away from the structure.

In another advantageous embodiment, an apparatus comprises a compositeelongate member, a channel, and a number of composite structures. Thecomposite elongate member has a side configured for attachment to astructure. The channel is on the side and extends along a length of thecomposite elongate member. The number of composite structures isconfigured for placement in the channel and configured to attach aportion of the side of the composite elongate member to the structure.The number of composite structures has layers oriented substantiallyperpendicular to a surface of the structure configured to increase acapacity of the composite elongate member to withstand forces that pullthe composite elongate member away from the structure.

In yet another advantageous embodiment, an apparatus comprises acomposite elongate member, a channel, and a number of compositestructures. The composite elongate member has a side configured forattachment to a structure. The channel is on the side and extends alonga length of the composite elongate member. The number of compositestructures is configured for placement in the channel and configured toattach a portion of the side of the composite elongate member to thestructure. A composite structure in the number of composite structurescomprises layers having different orientations selected to increase acapacity of the composite elongate member to withstand forces that pullthe composite elongate member away from the structure.

With reference now to FIG. 3, an illustration of a structural system isdepicted in accordance with an advantageous embodiment. In theseillustrative examples, structural system 300 is depicted in block form.Structural system 300 is located in aircraft 301 in these illustrativeexamples. As depicted, structural system 300 comprises compositeelongate member 302, number of composite structures 304, and structure306.

In these depicted examples, composite elongate member 302 is formed fromlayers 312 of composite material 314. For example, layers 312 ofcomposite material 314 are laid up and shaped into shape 316 forcomposite elongate member 302. Shape 316 may be T-shape 317 in theseillustrative examples.

As depicted, T-shape 317 for composite elongate member 302 is formed byfirst section 320 and second section 322 of composite elongate member302. In these illustrative examples, first section 320 may be referredto as a base section, and second section 322 may be referred to as avertical section. First section 320 and second section 322 may be partof the same structure in these examples. Of course, in otherillustrative examples, first section 320 and second section 322 may beformed from different structures.

Second section 322 is positioned substantially perpendicular to firstsection 320 to form T-shape 317 for composite elongate member 302. Inparticular, second section 322 is the portion of composite elongatemember 302 that extends away from first section 320 in a direction thatis substantially perpendicular to first section 320.

In these illustrative examples, first section 320 is substantiallyplanar. Further, first section 320 is a discontinuous section. Inparticular, first section 320 may be discontinuous where second section322 meets first section 320.

Second section 322 meets first section 320 at first location 321 andsecond location 323 of second section 322. First location 321 of secondsection 322 has first curved shape 324 with first radius 326. Secondlocation 323 of second section 322 has second curved shape 328 withsecond radius 330.

First radius 326 is a radius for a circle that substantially fits firstcurved shape 324. Second radius 330 is a radius for a circle thatsubstantially fits second curved shape 328. In these illustrativeexamples, first radius 326 may be substantially equal to second radius330.

First section 320 and second section 322 are positioned relative to eachother to form channel 332. In particular, channel 332 is formed betweenfirst location 321 and second location 323 of second section 322. Firstradius 326 of first curved shape 324 for first location 321 and secondradius 330 of second curved shape 328 for second location 323 determineshape 333 of channel 332.

In these illustrative examples, channel 332 is formed at first side 334of composite elongate member 302. Channel 332 extends along a length ofcomposite elongate member 302 in these examples. Composite elongatemember 302 also has second side 331 opposite to first side 334.

First side 334 may be, for example, a base side for both first section320 and second section 322. First side 334 is configured for attachmentto structure 306. Structure 306 may be, for example, without limitation,a skin panel, a rib, a spar, a base charge, a base plate, and/or someother suitable type of structure.

In one illustrative example, first side 334 of first section 320 ofcomposite elongate member 302 is substantially planar. Structure 306 maybe attached to first side 334 of first section 320 such that surface 337of structure 306 directly contacts first side 334 of first section 320in this illustrative example.

In these illustrative examples, a first component, such as structure306, may be attached to a second component, such as composite elongatemember 302, in a number of different ways. For example, a firstcomponent may be attached to a second component by bonding, curing,fastening, gluing, connecting, and/or attaching in some other suitablemanner the two components to each other.

First side 334 of second section 322 at first location 321 and secondlocation 323 forms first wall 338 and second wall 340 of channel 332. Inthis manner, first side 334 of second section 322 at first location 321and second location 323 may not directly contact surface 337 ofstructure 306 when structure 306 is attached to composite elongatemember 302. Further, when attached to composite elongate member 302,surface 337 of structure 306 forms third wall 341.

Number of composite structures 304 may be placed into channel 332.Number of composite structures 304 may be comprised of layers 346 ofcomposite material 348. As depicted, number of composite structures 304has shape 350 that substantially conforms to shape 333 of channel 332.Number of composite structures 304 forms filler structure 336 forchannel 332. Filler structure 336 may be referred to as a noodle inthese illustrative examples. Each of number of composite structures 304is a segment of filler structure 336.

For example, number of composite structures 304 may comprise a basesegment, a top segment, and a set of intermediate segments locatedbetween the base segment and the top segment. As used herein, a “set ofitems” means zero or more items. For example, a set of intermediatesegments may be an empty set or null set.

In these illustrative examples, number of composite structures 304 hasfirst number of characteristics 352 that substantially match secondnumber of characteristics 354 for composite elongate member 302. Firstnumber of characteristics 352 and second number of characteristics 354may comprise, for example, without limitation, at least one of acoefficient of thermal expansion, a Young's modulus, and other suitablecharacteristics.

As one illustrative example, layers 346 for number of compositestructures 304 may have configuration 351. Configuration 351 for layers346 is selected such that first number of characteristics 352 for numberof composite structures 304 substantially matches second number ofcharacteristics 354 for composite elongate member 302. For example, withconfiguration 351, a value for a Young's modulus for number of compositestructures 304 may be within a desired range from a value for a Young'smodule for composite elongate member 302.

Further, layers 346 for number of composite structures 304 may havefirst arrangement 353 that is substantially equal to second arrangement355 for layers 312 for composite elongate member 302. First arrangement353 for layers 346 of number of composite structures 304 is anarrangement of layers 346 relative to axis 357 through compositeelongate member 302. In particular, first arrangement 353 for layers 346is an arrangement of fibers in layers 346 relative to axis 357 throughcomposite elongate member 302.

As one illustrative example, first arrangement 353 may comprise about 50percent of layers 346 arranged about 0 degrees relative to axis 357,about 40 percent of layers 346 arranged about 45 degrees relative toaxis 357, and about 10 percent of layers 346 arranged about 90 degreesrelative to axis 357. In this illustrative example, second arrangement355 for layers 312 of composite elongate member 302 may havesubstantially the same percentages of layers 312 arranged substantiallythe same as first arrangement 353.

Number of composite structures 304 is configured to attach structure 306to composite elongate member 302. More specifically, number of compositestructures 304 attaches a portion of surface 337 of structure 306 to theportions of first side 334 at first location 321 and second location 323of second section 322 for composite elongate member 302.

When first number of characteristics 352 and second number ofcharacteristics 354 substantially match, capacity 356 of compositeelongate member 302 to withstand forces 358 increases. Forces 358 aregenerated when pressure is applied to composite elongate member 302 andstructure 306. For example, pressure may be applied to compositeelongate member 302 and structure 306 when aircraft 301 is beingoperated.

As one illustrative example, pressurization in a cabin of aircraft 301may cause pressure to be applied to composite elongate member 302 andstructure 306 when composite elongate member 302 and structure 306 arepart of a fuselage of aircraft 301. As another illustrative example,pressure may be applied to composite elongate member 302 and structure306 in response to the movement of fuel in a fuel tank in a wing ofaircraft 301 when composite elongate member 302 and structure 306 arepart of the wing of aircraft 301.

The pressure applied to composite elongate member 302 and structure 306may be in a direction substantially perpendicular to surface 337 ofstructure 306 in these illustrative examples. This pressure generatesforces 358. Forces 358 may include any forces that pull compositeelongate member 302 away from structure 306 when structure 306 isattached to composite elongate member 302 at first side 334. In otherwords, forces 358 include any forces that create a tensile load wherecomposite elongate member 302 is attached to structure 306.

Forces 358 may be substantially perpendicular to surface 337 ofstructure 306 in these illustrative examples. Further, forces 358 may besubstantially perpendicular to first side 334 of first section 320 ofcomposite elongate member 302.

The illustration of structural system 300 in FIG. 3 is not meant toimply physical or architectural limitations to the manner in which anadvantageous embodiment may be implemented. Other components in additionto and/or in place of the ones illustrated may be used. Some componentsmay be unnecessary. Also, the blocks are presented to illustrate somefunctional components. One or more of these blocks may be combinedand/or divided into different blocks when implemented in an advantageousembodiment.

For example, in some illustrative examples, more than one structure maybe attached to composite elongate member 302 at first side 334. As oneillustrative example, second structure 360 may be attached to structure306. For example, when structure 306 takes the form of a base charge,second structure 360 may be a skin panel that is attached to the basecharge. In some illustrative examples, the base charge may have a samearrangement as second arrangement 355 for composite elongate member 302.

As another illustrative example, third structure 362 may be attached tosecond side 331 of second section 322 of composite elongate member 302.Third structure 362 may be, for example, a rib, a spar, or some othersuitable type of structure.

In still other illustrative examples, structural system 300 may includeone or more composite members in addition to or in place of compositeelongate member 302 attached to structure 306. For example, a pluralityof stringers may be attached to structure 306 in the form of a skinpanel to form structural system 300.

In some cases, structural system 300 may be located in a platform otherthan aircraft 301. For example, structural system 300 may be located ina platform selected from at least one of a mobile platform, a stationaryplatform, a land-based structure, an aquatic-based structure, aspace-based structure, an aircraft, a surface ship, a tank, a personnelcarrier, a train, a spacecraft, a space station, a satellite, asubmarine, an automobile, a power plant, a bridge, a dam, amanufacturing facility, and a building.

With reference now to FIG. 4, an illustration of a perspective view of astructural system is depicted in accordance with an advantageousembodiment. In this illustrative example, structural system 400 is anexample of one implementation for structural system 300 in FIG. 3. Thedifferent components shown in this figure and in FIGS. 5, 6, and 9-17may be combined with components in FIG. 3, used with components in FIG.3, or a combination of the two. Additionally, some of the components inthis figure may be illustrative examples of how components shown inblock form in FIG. 3 may be implemented as physical structures.

As depicted, structural system 400 includes stringer 402, base charge404, skin 407, and noodle 406. Stringer 402 is an example of oneimplementation for composite elongate member 302 in FIG. 3. Base charge404 is an example of one implementation for structure 306 in FIG. 3, andnoodle 406 is an example of one implementation for filler structure 336in FIG. 3.

In this illustrative example, stringer 402 is a blade stringer. Stringer402 has first side 403 and second side 405. Further, stringer 402 hasfirst section 408 and second section 410. First section 408 and secondsection 410 are part of the same structure in this example. As depicted,first section 408 is a discontinuous section.

Second section 410 is positioned relative to first section 408 such thatsecond section 410 extends away from first section 408 in the directionof arrow 411. Arrow 411 has a direction that is substantiallyperpendicular to first section 408.

In this depicted example, second section 410 meets first portion 412 offirst section 408 at first location 414 of second section 410 and secondportion 416 of first section 408 at second location 418 of secondsection 410. First location 414 has first curved shape 422. Secondlocation 418 has second curved shape 424.

In this illustrative example, base charge 404 is attached to first side403 of stringer 402. In particular, first surface 426 of base charge 404contacts first side 403 of first section 408. Skin 407 is attached tosecond surface 427 of base charge 404. As depicted, first surface 426does not come into contact with first side 403 of second section 410.

Channel 428 is formed at first side 403 of stringer 402 between firstlocation 414 and second location 418 of second section 410. First side403 at first location 414 forms first wall 415 for channel 428, andfirst side 403 at second location 418 forms second wall 417 for channel428. Further, first surface 426 of base charge 404 forms third wall 419for channel 428. In this manner, channel 428 has shape 430 that isconical in this illustrative example.

Noodle 406 is located in channel 428. Noodle 406 comprises number ofcomposite structures 431. Number of composite structures 431 is anexample of one implementation for number of composite structures 304 inFIG. 3. Number of composite structures 431 is comprised of compositelayers 432. Composite layers 432 are layers of composite material.

The configuration of composite layers 432 is selected such that shape433 of noodle 406 substantially conforms to shape 430 of channel 428.Further, with noodle 406, a capacity for stringer 402 to withstandforces that pull stringer 402 away from base charge 404 and/or skin 407is increased as compared to when noodle 406 is absent or when adifferent type of noodle is present. These forces are in the directionof arrow 411.

As depicted, composite layers 432 for noodle 406 may be laid upsubstantially perpendicular to first side 403 and first surface 426 ofbase charge 404. Further, each of composite layers 432 may be arrangedhaving a particular angle with respect to axis 438 through stringer 402.

With reference now to FIG. 5, an illustration of a cross-sectional viewof a structural system is depicted in accordance with an advantageousembodiment. In this illustrative example, a cross-sectional view ofstructural system 400 from FIG. 4 is depicted taken along lines 5-5 inFIG. 4. Second section 410 of stringer 402 is positioned substantiallyperpendicular relative to first section 408 of stringer 402.

As depicted in this example, first curved shape 422 has first radius500. Further, second curved shape 424 has second radius 502. Firstradius 500 is a distance from the portion of first side 403 in firstlocation 414 that forms first curved shape 422 to point 504. Similarly,second radius 502 is a distance from the portion of first side 403 insecond location 418 that forms second curved shape 424 to point 506.

First curved shape 422 is an example of one implementation for firstcurved shape 324 in FIG. 3. Second curved shape 424 is an example of oneimplementation for second curved shape 328 in FIG. 3. In thisillustrative example, each of first curved shape 422 and second curvedshape 424 take the form of a portion of a circle. Of course, in otherillustrative examples, each of first curved shape 422 and second curvedshape 424 may take some other suitable form, such as, for example, aportion of an oval, an arc, a portion of an ellipse, or some othersuitable type of curved shape.

Turning now to FIG. 6, an illustration of a noodle is depicted inaccordance with an advantageous embodiment. In this illustrativeexample, noodle 406 from FIGS. 4-5 is depicted in greater detail. Asdepicted, noodle 406 has configuration 601 for number of compositestructures 431 comprising composite layers 432. In particular, number ofcomposite structures 431 includes composite structure 602, compositestructure 604, and composite structure 606.

Composite structure 602 is configured to contact third wall 419 ofchannel 428 and a base portion of first wall 415 and second wall 417 inFIG. 4. Composite structure 606 is configured to contact an apicalportion of first wall 415 and second wall 417 of channel 428 in FIG. 4.Composite structure 604 is located between composite structure 602 andcomposite structure 606. These composite structures form shape 433 fornoodle 406 that substantially conforms to shape 430 of channel 428 inFIG. 4.

Composite structure 602, composite structure 604, and compositestructure 606 may also be referred to as segments. For example,composite structure 602 may be a base segment, composite structure 606may be a top segment, and composite structure 604 may be an intermediatesegment between the base segment and the top segment.

In this illustrative example, composite structure 602 is formed fromcomposite layers 608, composite structure 604 is formed from compositelayers 610, and composite structure 606 is formed from composite layers612.

Configuration 601 for noodle 406 is selected such that shape 433 ofnoodle 406 substantially conforms to shape 430 of channel 428 in FIGS.4-5. As depicted, base 614 of composite structure 602 has length 616.Base 618 of composite structure 604 has length 620, and base 622 ofcomposite structure 606 has length 624.

Further, composite structure 602 has height 626, composite structure 604has height 628, and composite structure 606 has height 630.Additionally, composite structure 602 has angle 632 at base 614.Composite structure 604 has angle 634 at base 618. Composite structure606 has angle 636 at base 622.

With reference now to FIG. 7, an illustration of a table providingvalues for characteristics for composite layers is depicted inaccordance with an advantageous embodiment. In this illustrativeexample, table 700 provides values for characteristics for compositelayers 608 for composite structure 602 in noodle 406 in FIG. 6.

As depicted, table 700 includes composite layer 702, material 704, angle706, and thickness 708. Composite layer 702 identifies the particularlayer within composite layers 608. In these illustrative examples ofembodiments for composite layers 608, composite layers 608 include about20 layers of composite material.

Further, material 704 identifies the particular type of material fromwhich a layer is formed. In this illustrative example, all of compositelayers 608 are comprised of the same type of material. Angle 706identifies the angle at which a layer is arranged with respect to axis438 through stringer 402 in FIG. 4. As depicted, different layers may bearranged at different angles with respect to axis 438. Thickness 708identifies a thickness of a layer. In these illustrative examples, allof composite layers 608 have substantially the same thickness.

Composite layers 610 for composite structure 604 in FIG. 6 may havesubstantially the same characteristics as composite layers 608. Forexample, composite layers 610 may also include about 20 layers that arecomprised of substantially the same material and have substantially thesame thickness. Further, the different layers in composite layers 610may be arranged having substantially the same angles with respect toaxis 438 in FIG. 4 as composite layers 608.

With reference now to FIG. 8, an illustration of a table of embodimentsfor values for characteristics for composite layers is depicted inaccordance with an advantageous embodiment. In this illustrativeexample, table 800 provides values for characteristics for compositelayers 612 for composite structure 606 in noodle 406 in FIG. 6. Similarto table 700 in FIG. 7, table 800 includes composite layer 802, material804, angle 806, and thickness 808. The embodiments of each of thecharacteristics for layers described in each of first curved shape 422and second curved shape 424 may be combined with each of thecharacteristics for layers described in FIG. 7.

With reference now to FIG. 9, an illustration of a structural system ina wing is depicted in accordance with an advantageous embodiment. Inthis illustrative example, structural system 900 is located inside wing901 of an aircraft, such as aircraft 301 in FIG. 3.

Structural system 900 includes stringers 902 attached to skin panel 904.Stringers 902, in this illustrative example, are hat stringers. In thisdepicted example, filler structures (not shown in this view), such asfiller structure 336 in FIG. 3, may attach at least a portion of each ofstringers 902 to a base charge (not shown in this view). The basecharges (not shown) for stringers 902 connect stringers 902 to skinpanel 904.

Further, as illustrated, rib 906 is attached to stringers 902 and skinpanel 904. Rib 906 is a shear-tied rib in this depicted example. Thefiller structures (not shown) provide an increased capacity forstringers 902 to withstand forces that pull stringers 902 and/or rib 906away from skin panel 904 in the direction of arrow 908.

Turning now to FIG. 10, an illustration of a structural system in a wingis depicted in accordance with an advantageous embodiment. In thisillustrative example, structural system 1000 is located inside wing 1001of an aircraft, such as aircraft 301 in FIG. 3.

Structural system 1000 includes stringers 1002 attached to skin panel1004. Stringers 1002 are hat stringers in this depicted example.

Using filler structures (not shown), such as filler structure 336 inFIG. 3, to attach portions of stringers 1002 to skin panel 1004 providesan increased capacity for stringers 1002 to withstand forces that pullstringers 1002 away from skin panel 1004 in the direction of arrow 1008.This increased capacity to withstand these forces allows rib 1006 to beattached to stringers 1002 without being attached to skin panel 1004.

With reference now to FIGS. 11-14, illustrations of the different stagesof forming a structural system are depicted in accordance with anadvantageous embodiment. These figures provide an example of forming astructural system, such as structural system 300 in FIG. 3.

Turning now to FIG. 11, composite layers 1100 are laid up. Compositelayers 1100 are examples of one implementation for layers 312 ofcomposite material 314 in FIG. 3. Composite layers 1100 may be used toform a shape for a composite elongate member, such as shape 316 forcomposite elongate member 302 in FIG. 3.

In FIG. 12, heating element 1200 is placed over composite layers 1100.Heating element 1200 is a heating blanket in this illustrative example.Further, insulation element 1202 is placed over heating element 1200.Insulation element 1202 is an insulation blanket in this illustrativeexample. With heating element 1200 and insulation element over compositelayers 1100, composite layers 1100 are heated. In one illustrativeexample, composite layers 1100 are heated to about 110 degreesFahrenheit to shape composite layers 1100 to form a shape for astringer.

With reference now to FIG. 13, composite layers 1100 have been heated toform shape 1300. Composite layers 1100 with shape 1300 form stringer1302. In this illustrative example, channel 1304 is formed in stringer1302.

In FIG. 14, noodle 1400 is placed into channel 1304. Noodle 1400 may beimplemented using, for example, noodle 406 in FIG. 6. A base charge (notshown) may be placed over noodle 1400 and stringer 1302. A skin panel(not shown) may then be placed over the base charge. Stringer 1302,noodle 1400, the base charge, and the skin panel are then curedtogether. This curing may be performed by heating these differentcomponents together. For example, these different components may becured in an oven, an autoclave, or some other suitable device configuredto heat components.

In some cases, the components may be placed in a bag. These componentsmay then be heated, while a vacuum is applied to the bag to generatepressure and heat to form a structural system from the assembly of thecomponents.

With reference now to FIGS. 15-17, illustrations of panels from whichcomposite structures for noodles are formed are depicted in accordancewith an advantageous embodiment. These composite structures may be cutto form a number of noodles, such as noodle 406 in FIG. 6.

Turning now to FIG. 15, panel 1500 is comprised of composite layers.Panel 1500 has height 1501. Cuts are made into panel 1500 to formcomposite structures 1502, 1504, and 1506. These composite structureshave substantially the same shape and size. Composite structure 602 inFIG. 6 may be formed in a manner similar to the manner in whichcomposite structures 1502, 1504, and 1506 are formed. Of course,additional composite structures may be cut from panel 1500.

In FIG. 16, panel 1600 is comprised of composite layers. Panel 1600 hasheight 1601. Cuts are made into panel 1600 to form composite structures1602, 1604, and 1606. These composite structures have substantially thesame shape and size. Composite structure 604 in FIG. 6 may be formed ina manner similar to the manner in which composite structures 1602, 1604,and 1606 are formed.

Additionally, in FIG. 17, panel 1700 is comprised of composite layers.Panel 1700 has height 1701. Cuts are made into panel 1700 to formcomposite structures 1702 and 1704. These composite structures havesubstantially the same shape and size. Composite structure 606 in FIG. 6may be formed in a manner similar to the manner in which compositestructures 1702 and 1704 are formed.

The composite structures formed in FIGS. 15, 16, and 17 may be stackedon top of each other to form noodles. In one illustrative example,composite structure 1502 may be stacked on top of composite structure1602, which may be stacked on top of composite structure 1702 to form anoodle. These composite structures are stacked to form a noodle having ashape that substantially conforms to a particular channel in a compositeelongate member.

As another example, composite structure 1504 may be stacked on top ofcomposite structure 1604, which may be stacked on top of compositestructure 1704 to form another noodle. This noodle has a substantiallysame size and shape as the noodle formed by stacking compositestructures 1502, 1602, and 1702.

In other illustrative examples, other cuts may be made in other portionsof panel 1700, such as portion 1706, to form other composite structuresfor the noodle. As one illustrative example, cuts may be made in panel1700 to form composite structure 1708. Composite structure 1708 may beused in the same noodle as composite structures 1502, 1602, and 1702, orin a different noodle.

With reference now to FIG. 18, an illustration of a filler structure inthe form of a block diagram is depicted in accordance with anadvantageous embodiment. In this illustrative example, number ofcomposite structures 1800 is an example of one implementation for numberof composite structures 304 in FIG. 3.

In this illustrative example, number of composite structures 1800 formsfiller structure 1802 for channel 332 in FIG. 3 that is different fromfiller structure 336 in FIG. 3. Filler structure 1802 is another exampleof a noodle for channel 332 of composite elongate member 302 in FIG. 3.

In particular, number of composite structures 1800 may be placed intochannel 332 of composite elongate member 302 to attach structure 306 tocomposite elongate member 302 in FIG. 3. More specifically, number ofcomposite structures 1800 attaches a portion of surface 337 of structure306 to the portions of first side 334 at first location 321 and secondlocation 323 of second section 322 for composite elongate member 302 inFIG. 3.

As depicted in this example, number of composite structures 1800 iscomprised of layers 1804 of composite material 1806. In thisillustrative example, layers 1804 of composite material 1806 have shape1808 and orientation 1810. Shape 1808 and orientation 1810 for number ofcomposite structures 1800 are configured to increase capacity 356 ofcomposite elongate member 302 to withstand forces 358 that may pullcomposite elongate member 302 away from structure 306 in FIG. 3.

As one illustrative example, orientation 1810 of layers 1804 ofcomposite material 1806 may be a vertical orientation. In other words,layers 1804 of composite material 1806 may be orientated substantiallyperpendicular to surface 337 of structure 306 to increase capacity 356of composite elongate member 302 from FIG. 3 to withstand forces 358that pull composite elongate member 302 away from structure 306.

In this illustrative example, layers 1804 being oriented substantiallyperpendicular to surface 337 of structure 306 means that layers 1804 areoriented at an angle of about 90 degrees with respect to surface 337 ofstructure 306. In other words, layers 1804 are oriented substantiallyvertically with respect to surface 337 of structure 306 that may besubstantially horizontal.

Additionally, number of composite structures 1800 has shape 1808 thatsubstantially conforms to shape 333 of channel 332 in FIG. 3. In otherwords, layers 1804 of composite material 1806 may be formed with shape1808 to substantially conform to shape 333 of channel 332 in FIG. 3.

Each of number of composite structures 304 may be a segment of fillerstructure 1802. For example, number of composite structures 1800 maycomprise a number of segments that, when attached together, form fillerstructure 1802. For example, number of composite structures 1800 maycomprise a first segment, a second segment, and a set of intermediatesegments located between the base segment and the top segment. As usedherein, a “set of items” means zero or more items. For example, a set ofintermediate segments may be an empty set or null set.

As one illustrative example, number of composite structures 1800 maycomprise first segment 1812 and second segment 1814. First segment 1812may have first shape 1816 and second segment 1814 may have second shape1818. In these illustrative examples, first shape 1816 may besubstantially symmetrical to second shape 1818. When placed togethersuch that both first segment 1812 and second segment 1814 attach tosurface 337 of structure 306 in FIG. 3, first shape 1816 for firstsegment 1812 and second shape 1818 for second segment 1814 may formshape 1808 for number of composite structures 1800.

In these illustrative examples, number of composite structures 1800 hasfirst number of characteristics 1819 that substantially match secondnumber of characteristics 354 for composite elongate member 302 in FIG.3. First number of characteristics 1819 may include substantially thesame characteristics as second number of characteristics 354. Forexample, first number of characteristics 1819 may comprise, withoutlimitation, at least one of a coefficient of thermal expansion, aYoung's modulus, and other suitable characteristics.

As one illustrative example, layers 1804 for number of compositestructures 1800 may have configuration 1820. Configuration 1820 forlayers 1804 is selected such that first number of characteristics 1819for number of composite structures 1800 substantially matches secondnumber of characteristics 354 for composite elongate member 302 in FIG.3. For example, with configuration 1820, a value for a Young's modulusfor number of composite structures 1800 may be within a desired rangefrom a value for a Young's modulus for composite elongate member 302 inFIG. 3.

When first number of characteristics 1819 for number of compositestructures 1800 and second number of characteristics 354 for compositeelongate member 302 in FIG. 3 substantially match, capacity 356 ofcomposite elongate member 302 to withstand forces 358 increases. Forces358 are generated when pressure is applied to composite elongate member302 and structure 306. For example, pressure may be applied to compositeelongate member 302 and structure 306 when aircraft 301 is beingoperated.

In particular, when layers 1804 of composite material 1806 are orientedsubstantially perpendicular to surface 337 of composite elongate member302 in FIG. 3, the number of inconsistencies in filler structure 1802that form substantially parallel to surface 337 of composite elongatemember 302 may be reduced. For example, delamination of layers 1804and/or the growth of other inconsistencies substantially parallel tosurface 337 of composite elongate member 302 may be substantiallyarrested.

The illustration of number of composite structures 1800 in FIG. 18 isnot meant to imply physical or architectural limitations to the mannerin which an advantageous embodiment may be implemented. Other componentsin addition to and/or in place of the ones illustrated may be used. Somecomponents may be unnecessary. Also, the blocks are presented toillustrate some functional components. One or more of these blocks maybe combined and/or divided into different blocks when implemented in anadvantageous embodiment. For example, in some illustrative examples,number of composite structures 1800 may include segments in addition tofirst segment 1812 and second segment 1814.

With reference now to FIG. 19, an illustration of a perspective view ofa structural system is depicted in accordance with an advantageousembodiment. In this illustrative example, structural system 1900 is anexample of one implementation for structural system 300 shown in blockform in FIG. 3 using number of composite structures 1800 in FIG. 18. Inparticular, structural system 1900 includes stringer 1902, base charge1904, skin 1907, and noodle 1906. Stringer 1902 is an example of oneimplementation for composite elongate member 302 in FIG. 3. Base charge1904 is an example of one implementation for structure 306 shown inblock form in FIG. 3, and noodle 1906 is an example of oneimplementation for filler structure 1802 in FIG. 18.

In this illustrative example, stringer 1902 is a blade stringer.Stringer 1902 has first side 1903 and second side 1905. Further,stringer 1902 has first section 1908 and second section 1910. Firstsection 1908 and second section 1910 are part of the same structure inthis example. As depicted, first section 1908 is a discontinuoussection.

Second section 1910 is positioned relative to first section 1908 suchthat second section 1910 extends away from first section 1908 in thedirection of arrow 1911. Arrow 1911 has a direction that issubstantially perpendicular to first section 1908.

In this depicted example, second section 1910 meets first portion 1912of first section 1908 at first location 1914 of second section 1910 andsecond portion 1916 of first section 1908 at second location 1918 ofsecond section 1910. First location 1914 has first curved shape 1922.Second location 1918 has second curved shape 1924.

In this illustrative example, base charge 1904 is attached to first side1903 of stringer 1902. In particular, first surface 1926 of base charge1904 contacts first side 1903 of first section 1908. Skin 1907 isattached to second surface 1927 of base charge 1904. As depicted, firstsurface 1926 does not come into contact with first side 1903 of secondsection 1910.

Noodle 1906 is located in channel 1928. Noodle 1906 comprises number ofcomposite structures 1931. Number of composite structures 1931 is anillustrative example of one implementation for number of compositestructures 1800 shown in block form in FIG. 18. Number of compositestructures 1931 is comprised of composite layers 1932. Composite layers1932 are layers of composite material, such as layers 1804 of compositematerial 1806 shown in block form in FIG. 18.

The configuration of composite layers 1932 is selected such that shape1933 of noodle 1906 substantially conforms to shape 1930 of channel1928. Further, with noodle 1906, a capacity for stringer 1902 towithstand forces that pull stringer 1902 away from base charge 1904and/or skin 1907 is increased as compared to when noodle 1906 is absentor when a different type of noodle is present. These forces are in thedirection of arrow 1911.

As depicted, composite layers 1932 for noodle 1906 may be orientedsubstantially perpendicular to first side 1903 of first section 1908 andfirst surface 1926 of base charge 1904. In other words, composite layers1932 are oriented at an angle of about 90 degrees with respect to firstsurface 1926 of base charge 1904. More specifically, composite layers1932 are oriented in the direction of arrow 1911 in this depictedexample.

Additionally, in this illustrative example, adhesive and/or some othersuitable type of material may be used to fill in any gaps or spacesbetween noodle 1906 and first side 1903 of stringer 1902 at firstlocation 1914 and second location 1918. In this manner, gaps or spacesin channel 1928 may not be present when stringer 1902, base charge 1904,and noodle 1906 are attached together.

With reference now to FIG. 20, an illustration of panels from whichcomposite structures for noodles are formed is depicted in accordancewith an advantageous embodiment. These composite structures may be cutto form a number of composite structures, such as number of compositestructures 1800 shown in block form in FIG. 18. In particular, thesecomposite structures may be cut to form a noodle, such as noodle 1906 inFIG. 19.

As depicted, panel 2000 and panel 2002 are comprised of compositelayers. Cut 2004 is made into panel 2000 to form composite structure2006. Cut 2008 is made into panel 2002 to form composite structure 2010.These composite structures have substantially the same shape and size.The leftover portions of panel 2000 and panel 2002 may be used to formother composite structures, depending on the implementation.

With reference now to FIG. 21, an illustration of a laminate for anoodle is depicted in accordance with an advantageous embodiment. Inthis illustrative example, composite structure 2006 and compositestructure 2010 from FIG. 20 may be attached together to form laminate2100 with shape 2102. In particular, composite structure 2006 andcomposite structure 2010 are rotated to form laminate 2100 with shape2102. Laminate 2100 may be used to form a noodle for a compositeelongate member in the form of a stringer.

Shape 2102 for laminate 2100 may be larger than a shape for the channelinto which the final noodle is to be placed. In particular, shape 2102for laminate 2100 is configured such that after curing, laminate 2100may have a final shape that substantially conforms to the shape of thechannel in the stringer. Laminate 2100 may be cured by applying heatand/or pressure to laminate 2100 to form the noodle for the stringer.

Of course, in other illustrative examples, laminate 2100 having shape2102 may be formed from a single panel by making two cuts at about 45degrees with respect to the surface of the panel and with an angle ofabout 90 degrees between the two cuts.

With reference now to FIG. 22, an illustration of a filler structure inthe form of a block diagram is depicted in accordance with anadvantageous embodiment. In this illustrative example, number ofcomposite structures 2200 is an example of one implementation for numberof composite structures 304 shown in block form in FIG. 3.

In this illustrative example, number of composite structures 2200 formsfiller structure 2202 for channel 332 shown in block form in FIG. 3.Filler structure 2202 is another example of a noodle for channel 332 ofcomposite elongate member 302 shown in block form in FIG. 3.

In particular, number of composite structures 2200 may be placed intochannel 332 of composite elongate member 302 to attach structure 306 tocomposite elongate member 302 shown in block form in FIG. 3. Morespecifically, number of composite structures 2200 attaches a portion ofsurface 337 of structure 306 to the portions of first side 334 at firstlocation 321 and second location 323 of second section 322 for compositeelongate member 302 shown in block form in FIG. 3.

As depicted in this example, number of composite structures 2200 iscomprised of layers 2204 of composite material 2206. In thisillustrative example, layers 2204 of composite material 2206 have shape2208. Shape 2208 for number of composite structures 2200 is configuredto increase capacity 356 of composite elongate member 302 to withstandforces 358 that may pull composite elongate member 302 away fromstructure 306 shown in block form in FIG. 3. In particular, number ofcomposite structures 2200 has shape 2208 that substantially conforms toshape 333 of channel 332 shown in block form in FIG. 3. In other words,layers 2204 of composite material 2206 may be formed with shape 2208 tosubstantially conform to shape 333 of channel 332 shown in block form inFIG. 3.

In this illustrative example, each of number of composite structures2200 may be a segment of filler structure 2202. For example, number ofcomposite structures 2200 may comprise a number of segments that whenattached together form filler structure 2202. In one illustrativeexample, number of composite structures 2200 may comprise only segment2212 comprising layers 2204 of composite material 2206.

Layers 2204 of composite material 2206 in segment 2212 have differentorientations 2210 with respect to axis 357 through composite elongatemember 302 shown in block form in FIG. 3. Orientations 2210 of layers2204 of composite material 2206 in number of composite structures 2200may be selected to increase capacity 356 of composite elongate member302 to withstand forces 358 that may pull composite elongate member 302away from structure 306 shown in block form in FIG. 3.

For example, layers 2204 may be laid up with configuration 2214.Configuration 2214 for layers 2204 may comprise groups 2216 of layers2204. As used herein, a group of layers is two or more layers. As oneillustrative example, layers 2204 may be formed into groups 2216 oflayers 2204 in which each group in groups 2216 comprises two layers.These two layers may have different orientations 2210.

Group 2218 is an example of one of groups 2216. In one illustrativeexample, group 2218 comprises first layer 2220 and second layer 2222.Second layer 2222 may be laid up on top of first layer 2220. First layer2220 may comprise fibers that are arranged at an angle of about 0degrees with respect to axis 357 through composite elongate member 302shown in block form in FIG. 3. Further, second layer 2222 may comprisefibers that are arranged at an angle selected from one of about 45degrees with respect to axis 357 and about 90 degrees with respect toaxis 357.

In configuration 2214 for layers 2204, all of the groups in groups 2216may have two layers arranged in substantially the same manner as firstlayer 2220 and second layer 2222 for group 2218. In particular, theangle at which the fibers for second layer 2222 are arranged in thedifferent groups in groups 2216 may be alternated between about 45degrees with respect to axis 357 and about 90 degrees with respect toaxis 357 through composite elongate member 302 shown in block form inFIG. 3. In other words, two adjacent groups in groups 2216 may not havesecond layer 2222 with fibers having the same angle with respect to axis357.

In another illustrative example, group 2218 may comprise layers inaddition to first layer 2220 and second layer 2222. For example, group2218 also may include third layer 2224 and fourth layer 2226. Secondlayer 2222 may be laid up on first layer 2220. Third layer 2224 may belaid up on second layer 2222. Fourth layer 2226 may be laid up on thirdlayer 2224.

When group 2218 comprises four layers, first layer 2220 and fourth layer2226 may comprise fibers that are arranged at an angle of about 0degrees with respect to axis 357 through composite elongate member 302in FIG. 3. Second layer 2222 and third layer 2224 may comprise fibersthat are arranged at an angle selected from one of about 45 degrees withrespect to axis 357 and about 90 degrees with respect to axis 357. Inthis manner, second layer 2222 and third layer 2224 may be “sandwiched”between first layer 2220 and fourth layer 2226 having fibers arranged atthe angle of about 0 degrees with respect to axis 357 through compositeelongate member 302.

Additionally, in this illustrative example, groups 2216 of layers 2204may be formed as a laminate that has a shape larger than shape 333 ofchannel 332 shown in block form in FIG. 3. For example, layers 2204 forthe different groups in groups 2216 that are laid up to form thelaminate may be wider than shape 333 of channel 332 in a directionsubstantially perpendicular to axis 357 through composite elongatemember 302. The shape for the laminate is formed such that after curingof the laminate to form filler structure 2202, filler structure 2202 hasshape 2208 that substantially conforms to shape 333 of channel 332 shownin block form in FIG. 3.

Further, in this illustrative example, layers 2204 may have differentwidths, depending on the implementation. As one illustrative example,layers 2204 may have widths that decrease in value from a base of fillerstructure 2202 to a top of filler structure 2202. In other words, layers2204 that are closer to structure 306 when filler structure 2202 isplaced in channel 332 in FIG. 3 may be wider as compared to layers 2204that are further away from structure 306.

In this manner, layers 2204 may have widths that form shape 2208 similarto shape 333 of channel 332 shown in block form in FIG. 3. Inparticular, these widths may be selected such that the widths of layers2204 are wider than shape 333 of channel 332 prior to curing of layers2204 to form filler structure 2202. As a result, prior to curing, layers2204 may have shape 2208 with a size that is slightly larger than thesize of shape 333 of channel 332. When layers 2204 are cured to formfiller structure 2202, the widths of layers 2204 may be reduced suchthat shape 2208 of filler structure 2202 has a size that substantiallyconforms to shape 333 of channel 332.

In these illustrative examples, number of composite structures 2200 hasfirst number of characteristics 2228 that substantially matches secondnumber of characteristics 354 for composite elongate member 302 shown inblock form in FIG. 3. First number of characteristics 2228 may includesubstantially the same characteristics as second number ofcharacteristics 354. For example, first number of characteristics 2228may comprise, without limitation, at least one of a coefficient ofthermal expansion, a Young's modulus, and other suitablecharacteristics.

In this illustrative example, configuration 2214 for groups 2216 oflayers 2204 is selected such that first number of characteristics 2228for number of composite structures 2200 substantially matches secondnumber of characteristics 354 for composite elongate member 302 in FIG.3. For example, with configuration 2214, a value for a Young's modulusfor number of composite structures 2200 may be within a desired rangefrom a value for a Young's modulus for composite elongate member 302shown in block form in FIG. 3.

When first number of characteristics 2228 for number of compositestructures 2200 and second number of characteristics 354 for compositeelongate member 302 shown in block form in FIG. 3 substantially match,capacity 356 of composite elongate member 302 to withstand forces 358increases.

The illustration of number of composite structures 2200 in FIG. 22 isnot meant to imply physical or architectural limitations to the mannerin which an advantageous embodiment may be implemented.

Other components in addition to and/or in place of the ones illustratedmay be used. Some components may be unnecessary. Also, the blocks arepresented to illustrate some functional components. One or more of theseblocks may be combined and/or divided into different blocks whenimplemented in an advantageous embodiment. For example, in someillustrative examples, fewer or more layers than the ones described maybe present in group 2218.

With reference now to FIG. 23, an illustration of a front view of astructural system is depicted in accordance with an advantageousembodiment. In this illustrative example, structural system 2300 is anexample of one implementation for structural system 300 in FIG. 3 usingnumber of composite structures 2200 in FIG. 22. In particular,structural system 2300 includes stringer 2302, base charge 2304, skin2307, and noodle 2306. Stringer 2302 is an example of one implementationfor composite elongate member 302 shown in block form in FIG. 3. Basecharge 2304 is an example of one implementation for structure 306 inFIG. 3, and noodle 2306 is an example of one implementation for fillerstructure 2202 in FIG. 22.

In this illustrative example, stringer 2302 is a blade stringer.Stringer 2302 has first side 2303 and second side 2305. Further,stringer 2302 has first section 2308 and second section 2310. Firstsection 2308 and second section 2310 are part of the same structure inthis example. As depicted, first section 2308 is a discontinuoussection.

Second section 2310 is positioned relative to first section 2308 suchthat second section 2310 extends away from first section 2308 in thedirection of arrow 2311. Arrow 2311 has a direction that issubstantially perpendicular to first section 2308.

In this depicted example, second section 2310 meets first portion 2312of first section 2308 at first location 2314 of second section 2310 andsecond portion 2316 of first section 2308 at second location 2318 ofsecond section 2310. First location 2314 has first curved shape 2322.Second location 2318 has second curved shape 2324.

In this illustrative example, base charge 2304 is attached to first side2303 of stringer 2302. In particular, first surface 2326 of base charge2304 contacts first side 2303 of first section 2308. Skin 2307 isattached to second surface 2327 of base charge 2304. As depicted, firstsurface 2326 does not come into contact with first side 2303 of secondsection 2310.

Noodle 2306 may be inserted into channel 2328. As depicted, noodle 2306comprises composite structure 2331. Composite structure 2331 is anexample of one implementation for number of composite structures 2200 inFIG. 22. Composite structure 2331 takes the form of one segment in thisdepicted example. Composite structure 2331 is comprised of compositelayers 2332. Composite layers 2332 are layers of composite material,such as layers 2204 of composite material 2206 in FIG. 22.

As illustrated, composite layers 2332 may have widths 2334 that arewider than shape 2330 of channel 2328. However, widths 2334 may beselected such that composite layers 2332 may shrink to form shape 2333with a size that substantially conforms to the size of shape 2330 ofchannel 2328. In particular, the configuration of composite layers 2332is selected such that shape 2333 of noodle 2306 substantially conformsto shape 2330 of channel 2328 after noodle 2306 has been cured.

Further, with noodle 2306, a capacity for stringer 2302 to withstandforces that pull stringer 2302 away from base charge 2304 and/or skin2307 is increased as compared to when noodle 2306 is absent or when adifferent type of noodle is present. These forces are in the directionof arrow 2311.

In this illustrative example, composite layers 2332 for noodle 2306 mayhave different orientations with respect to an axis (not shown) throughstringer 2302. This axis (not shown) may be through the page andsubstantially perpendicular to arrow 2311. In this illustrative example,composite layers 2332 include 34 layers.

Additionally, in this illustrative example, adhesive and/or some othersuitable type of material may be used to fill in any gaps or spacesbetween noodle 2306 and first side 2303 of stringer 2302 at firstlocation 2314 and second location 2318. In this manner, gaps or spacesin channel 2328 may not be present when stringer 2302, base charge 2304,and noodle 2306 are attached together.

With reference now to FIG. 24, an illustration of a table for widths andorientation angles for composite layers in a noodle is depicted inaccordance with an advantageous embodiment. In this illustrativeexample, table 2400 includes composite layers 2402, widths 2404, andorientation angles 2406.

As depicted, composite layers 2402 identify the different compositelayers in composite layers 2332 within noodle 2306 in FIG. 23. Widths2404 identify the different widths in widths 2334 for the differentcomposite layers in composite layers 2332. Further, orientation angles2406 identify the angles in which the fibers for the different compositelayers in composite layers 2332 are arranged with respect to the axis(not shown in FIG. 23) through stringer 2302.

With reference now to FIG. 25, an illustration of a flowchart of aprocess for increasing a pull-off capacity for a composite elongatemember is depicted in accordance with an advantageous embodiment. Theprocess illustrated in FIG. 25 may be implemented to increase a pull-offcapacity for composite elongate member 302 in FIG. 3.

The process begins by operating an aircraft (operation 2500). Inparticular, in operation 2500, the process applies a pressure to thecomposite elongate member and a structure attached to a side of thecomposite elongate member. The composite elongate member may be, forexample, a stringer. The structure may be, for example, a skin panel.

In response to operation of the aircraft, the process generates forcesconfigured to pull the composite elongate member away from a structure(operation 2502), with the process terminating thereafter. The forcesare in a direction substantially perpendicular to a surface of thestructure. In this illustrative example, a channel extends along alength of the composite elongate member on the side of the compositeelongate member attached to the structure.

A number of composite structures is configured to attach a portion ofthe side of the composite elongate member to the structure such that acapacity of the composite elongate member to withstand the forces thatpull the composite elongate member away from the structure is increased.The capacity of the composite elongate member to withstand the forcesthat pull the composite elongate member away from the structure is thepull-off capacity for the composite elongate member.

In this illustrative example, the number of composite structures thatattaches the portion of the side of the composite elongate member to thestructure may be selected from a number of different configurations. Forexample, the number of composite structures may have configuration 351for number of composite structures 304 in FIG. 3, configuration 1820 fornumber of composite structures 1800 in FIG. 18, or configuration 2214for number of composite structures 2200 in FIG. 22.

With reference now to FIG. 26, an illustration of a flowchart of aprocess for forming a structural system is depicted in accordance withan advantageous embodiment. The process illustrated in FIG. 26 may beimplemented to form structural system 300 in FIG. 3.

The process begins by laying up layers for a composite elongate member(operation 2600). These layers may be, for example, layers of compositematerial. The composite elongate member may be, for example, a stringer,a stiffener, or some other suitable type of composite elongate member.

The process then shapes the layers to form a shape for the compositeelongate member with a side configured for attachment to a structure(operation 2602). Operation 2602 may be performed by, for example,heating the layers to form the shape for the composite elongate member.The structure may be, for example, a skin panel, a base charge, and/orsome other structure having a substantially planar surface. A channelextending along a length of the composite elongate member is present onthe side configured for attachment to the structure.

Thereafter, the process places a number of composite structures in thechannel (operation 2604). In operation 2604, the number of compositestructures may have configuration 351 for number of composite structures304 in FIG. 3, configuration 1820 for number of composite structures1800 in FIG. 18, or configuration 2214 for number of compositestructures 2200 in FIG. 22.

The number of composite structures forms a filler structure that isconfigured to attach a portion of the side of the composite elongatemember to the structure. The number of composite structures increases acapacity of the composite elongate member to withstand forces that pullthe composite elongate member away from the structure.

The process then positions the structure with respect to the side of thecomposite elongate member (operation 2606). For example, in operation2606, the structure may be placed over the composite elongate membersuch that a surface of the structure directly contacts at least aportion of the side of the composite structure. The process then curesthe layers in the shape for the composite elongate member with thenumber of composite members in the channel and the structure to form thestructural system (operation 2608), with the process terminatingthereafter.

With reference now to FIG. 27, an illustration of a flowchart of aprocess for forming a filler structure is depicted in accordance with anadvantageous embodiment. The process illustrated in FIG. 27 may beimplemented to form filler structure 336 in FIG. 3.

The process lays up composite layers for forming a composite structurefor placement in a portion of a channel in a composite elongate member(operation 2700). The composite structure is for a filler structure tobe placed in the channel of the composite elongate member. The compositelayers for the composite structure are then compacted to form a panel(operation 2702). This compaction is performed by applying pressure tothe composite layers to form the panel. The panel has a height that issubstantially the height desired for the composite structure.

Thereafter, the process makes cuts into the panel to form the compositestructure (operation 2704). In operation 2704, the cuts may be made atangles selected to form the composite structure having a size and shapethat substantially conforms to the corresponding portion of the channel.In some illustrative examples, the cuts may be made such that the sizeand shape of the composite structure reduces after curing to a size andshape that substantially conforms to the corresponding portion of thechannel.

The process then determines whether any additional composite structuresare needed to form a number of composite structures needed for thefiller structure (operation 2706). If additional composite structuresare not needed, the process determines whether more than one compositestructure has been formed for the filler structure (operation 2708). Ifmore than one composite structure has not been formed for the fillerstructure, the process terminates. If more than one composite structurehas been formed, the process attaches the composite structures to eachother (operation 2710), with the process terminating thereafter. Inoperation 2710, the composite structures may be attached to each otherin a stacked form, side by side, and/or in some other suitable mannersuch that an overall shape for the composite structures substantiallyconforms to the shape of the channel in the composite elongate member.

With reference again to operation 2706, if additional compositestructures are needed for the filler structure, the process returns tooperation 2700 as described above to form a new composite structure.

The flowcharts and block diagrams in the different depicted embodimentsillustrate the architecture, functionality, and operation of somepossible implementations of apparatuses and methods in an advantageousembodiment. In this regard, each block in the flowcharts or blockdiagrams may represent a module, segment, function, and/or a portion ofan operation or step.

In some alternative implementations of an advantageous embodiment, thefunction or functions noted in the block may occur out of the ordernoted in the figures. For example, in some cases, two blocks shown insuccession may be executed substantially concurrently or the blocks maysometimes be executed in the reverse order, depending upon thefunctionality involved. Also, other blocks may be added in addition tothe illustrated blocks in a flowchart or block diagram.

Thus, the different advantageous embodiments provide a stringer with anincreased capacity to withstand forces that may pull the stringer awayfrom another structure to which the stringer is attached. In oneadvantageous embodiment, a structural system comprises a compositeelongate member, a number of composite structures, and a structure. Thecomposite elongate member has a side configured for attachment to thestructure and a channel on the side of the composite elongate member.The channel extends along a length of the composite elongate member. Thenumber of composite structures is configured for placement in thechannel. Further, the number of composite structures is configured toattach a portion of the side of the composite elongate member to thestructure. The number of composite structures is configured to increasea capacity of the composite elongate member to withstand forces thatpull the composite elongate member away from the structure.

In another advantageous embodiment, an apparatus comprises a compositeelongate member, a channel, and a number of composite structures. Thecomposite elongate member has a side configured for attachment to astructure. The channel is on the side and extends along a length of thecomposite elongate member. The number of composite structures isconfigured for placement in the channel and configured to attach aportion of the side of the composite elongate member to the structure.The number of composite structures has layers oriented substantiallyperpendicular to a surface of the structure configured to increase acapacity of the composite elongate member to withstand forces that pullthe composite elongate member away from the structure.

In yet another advantageous embodiment, an apparatus comprises acomposite elongate member, a channel, and a number of compositestructures. The composite elongate member has a side configured forattachment to a structure. The channel is on the side and extends alonga length of the composite elongate member. The number of compositestructures is configured for placement in the channel and configured toattach a portion of the side of the composite elongate member to thestructure.

In this advantageous embodiment, a composite structure in the number ofcomposite structures comprises layers having different orientationsselected to increase a capacity of the composite elongate member towithstand forces that pull the composite elongate member away from thestructure. The composite structure may comprise groups of the layersthat are laid up to form the composite structure. A group in the groupsof the layers may have a first layer in which first fibers in the firstlayers are arranged at an angle of about 0 degrees with respect to anaxis through the composite elongate member and a second layer in whichsecond fibers in the second layer are arranged at an angle selected fromone of about 45 degrees with respect to the axis through the compositeelongate member and about 90 degrees with respect to the axis throughthe composite elongate member.

In this manner, the different advantageous embodiments provide astructural system that allows an increased number of intermediate ribsas compared to shear-tied ribs to be used in the wing of an aircraft.Intermediate ribs have a reduced weight as compared to shear-tied ribs.With stringers having an increased capacity to withstand forces that maypull the stringers away from a skin panel to which the stringers areattached, intermediate ribs may be used in addition to and/or in placeof shear-tied ribs in a wing to reduce the weight of the wing.

The description of the different advantageous embodiments has beenpresented for purposes of illustration and description and is notintended to be exhaustive or limited to the embodiments in the formdisclosed. Many modifications and variations will be apparent to thoseof ordinary skill in the art. Further, different advantageousembodiments may provide different advantages as compared to otheradvantageous embodiments. The embodiment or embodiments selected arechosen and described in order to best explain the principles of theembodiments, the practical application, and to enable others of ordinaryskill in the art to understand the disclosure for various embodimentswith various modifications as are suited to the particular usecontemplated.

1. An apparatus comprising: a composite elongate member having a sideconfigured for attachment to a surface of a structure; a channel on theside extending along a length of the composite elongate member; and anumber of composite structures configured for placement in the channeland configured to attach a portion of the side of the composite elongatemember to the structure, wherein the number of composite structures haslayers oriented substantially perpendicular to the surface of thestructure and is configured to increase a capacity of the compositeelongate member to withstand forces that pull the composite elongatemember away from the structure.
 2. The apparatus of claim 1, wherein thenumber of composite structures has a shape that substantially conformsto the shape of the channel.
 3. The apparatus of claim 1, wherein ashape of the number of composite structures is formed after curing alaminate comprising the layers for the number of composite structures toform the number of composite structures.
 4. The apparatus of claim 1,wherein the number of composite structures comprises: a first compositestructure; and a second composite structure, wherein the first compositestructure has a first shape that is symmetrical to a second shape forthe second composite structure.
 5. The apparatus of claim 1, wherein thenumber of composite structures has a first number of characteristicsthat substantially matches a second number of characteristics for thecomposite elongate member such that the capacity of the compositeelongate member to withstand the forces that pull the composite elongatemember away from the structure increases.
 6. The apparatus of claim 5,wherein the first number of characteristics and the second number ofcharacteristics comprise at least one of a coefficient of thermalexpansion and a Young's modulus.
 7. The apparatus of claim 6, whereinthe number of composite structures comprises layers having aconfiguration that results in a value for a first Young's modulus forthe number of composite structures that is within a desired range from avalue for a second Young's modulus for the composite elongate member. 8.The apparatus of claim 1, wherein the composite elongate membercomprises: a first section; and a second section positionedsubstantially perpendicular to the first section, wherein the secondsection meets the first section at a first location of the secondsection having a first curved shape with a first radius and a secondlocation of the second section having a second curved shape with asecond radius in which the first radius and the second radius aresubstantially equal, and wherein the first section and the secondsection are positioned with respect to each other to form the channelbetween the first location and the second location.
 9. The apparatus ofclaim 1, wherein the composite elongate member is selected from one of astringer and a stiffener.
 10. The apparatus of claim 1, wherein thestructure is selected from one of a skin panel, a spar, a rib, and abase charge.
 11. The apparatus of claim 1, wherein the compositeelongate member is a stringer, a side of the stringer is a first side,the structure is a skin panel attached to the first side of thestringer, and a rib is attached to a second side of the stringer that issubstantially opposite to the first side.
 12. The apparatus of claim 1,wherein the composite elongate member and the structure are located in aplatform selected from one of a mobile platform, a stationary platform,a land-based structure, an aquatic-based structure, a space-basedstructure, an aircraft, a surface ship, a tank, a personnel carrier, atrain, a spacecraft, a space station, a satellite, a submarine, anautomobile, a power plant, a bridge, a dam, a manufacturing facility,and a building.
 13. A structural system for an aircraft comprising: acomposite elongate member having a base section and a vertical sectionin which the vertical section extends away from the base section in adirection substantially perpendicular to the base section to form aT-shape, wherein the vertical section meets the base section at a firstlocation of the vertical section and a second location of the verticalsection in which the first location has a first curved shape and thesecond location has a second curved shape in which the first curvedshape and the second curved shape have a substantially same radius;wherein a channel is formed between the first location and the secondlocation and extends along a length of the composite elongate member;and wherein the composite elongate member has a first Young's modulus;and a filler structure comprising a number of composite structuresconfigured to conform to a shape of the channel and wherein the numberof composite structures has a second Young's modulus that is within adesired range from the first Young's modulus and has layers orientedsubstantially perpendicular to a surface of the base section and isconfigured to increase a capacity of the composite elongate member towithstand forces that pull the composite elongate member away from thebase section.
 14. The structural system of claim 13, wherein thecomposite member has a first coefficient of thermal expansion and thefiller structure has a second coefficient of thermal expansion that issubstantially equal to the first coefficient of thermal expansion.
 15. Amethod for increasing a pull-off capacity for a composite elongatemember, the method comprising: operating an aircraft; and generatingforces configured to pull the composite elongate member away from astructure attached to a side of the composite elongate member duringoperation of the aircraft, wherein a channel extends along a length ofthe composite elongate member on the side of the composite elongatemember attached to the structure and a number of composite structures inthe channel has layers oriented substantially perpendicular to a surfaceof the structure and configured to attach a portion of the side of thecomposite elongate member to the structure such that a capacity of thecomposite elongate member to withstand the forces that pull thecomposite elongate member away from the structure is increased.
 16. Themethod of claim 15, wherein operating the aircraft comprises: operatingthe aircraft such that pressure is applied to the composite elongatemember and the structure attached to the side of the composite elongatemember, wherein the pressure causes the forces to be generated.
 17. Themethod of claim 16, wherein the forces are in a direction substantiallyperpendicular to the surface of the structure.
 18. The method of claim15, wherein generating the forces configured to pull the compositeelongate member away from the structure in response to the operation ofthe aircraft comprises: generating the forces configured to pull thecomposite elongate member away from the structure during the operationof the aircraft such that a tensile load is created at a location wherethe composite elongate member is attached to the structure.
 19. Themethod of claim 15, wherein the composite elongate member is selectedfrom one of a stringer and a stiffener and the structure is selectedfrom one of a skin panel, a spar, a rib, and a base charge.
 20. Themethod of claim 15, wherein the composite elongate member and thestructure are located in a platform selected from one of a mobileplatform, a stationary platform, a land-based structure, anaquatic-based structure, a space-based structure, an aircraft, a surfaceship, a tank, a personnel carrier, a train, a spacecraft, a spacestation, a satellite, a submarine, an automobile, a power plant, abridge, a dam, a manufacturing facility, and a building.